Research on Deformation Characteristics and Design Optimization of Super-Large Cofferdam Enclosure Structure

Abstract

With the rapid development of urban transportation facilities, their construction inevitably encounters unfavorable conditions, such as rivers and lakes. When using the weir construction method to build transportation facilities in lakes, the design scheme for the pit slope excavation inside the cofferdam is related to the success or failure of the construction. In this study, the design scheme for pit excavations in lakes is discussed and analyzed using numerical simulation and on-site monitoring against the background of Jinji Lake Tunnel. The findings are as follows. (1) The greater the distance between the pit and the cofferdam, the smaller the impact of pit excavation on the cofferdam is; when the excavation depth is 10 m and the distance is more than 47 m, the deformation of the whole pile is less than 15 mm. (2) Under the condition that the platform width is kept the same, the smaller the height and width ratio is, the greater the safety factor will be, and under the condition that the height and width ratio is kept the same, the longer the platform width is, the greater the safety factor will be. (3) When the pit and cofferdam are far away from each other, different slope release design schemes have different effects on cofferdam deformation and stability. The results of this research can provide references and guidance for the design and construction of similar projects.

Keywords

• cofferdam
• tunnel
• foundation pit excavation
• slope